54 Summary Title of the paper: Experiments with flax for fibre production. Result of experiments respecting growth, cultivation, weeds and manuring in the years 1943(38)—1950(51). The present collocation concerns experiments with flax for fibre production during the years 1938—1950(51). The majority of the experiments were performed after 1943. For 1951 there is only a table giving the averages from the sort experiments of that year. Thanks to the establishment of the flax laboratory of the Swedish plant breeding association it has been possible to perform qualitative analyses of the experiments. Prior to 1943 the experiments were not analysed for quality. Through their organization »The national flax and hemp association» flax growers have provided the financial aid which was a prerequisite for the carrying out of the experiments on the present scale. The report of the experiments is rendered for the various districts in the following five groups: 1) South Halland (6a) 2) Southern middle country (2) and Southern Highland. (3) 3) The plainlands of W. Sweden excluding South Halland. (6b) 4) The Östgöta plain (5), South Bergslagen (7), Mälar-Hjälmar district (8) 5) North Bergslagen (9), Norrland (10, 11, 12) The figures in brackets refer to map on Page 6. The area of Swedish land devoted to flax has varied considerably. In the 18-sixties it comprized about 16500 hectares. In the opening years of the twentieth century it fell to under 1000 hectares but rose during the latter part of the first World War to 4000 hect. Interest in Swedish flax was kept alive between the wars by the circumstance that Swedish Arts and Crafts needed the raw material. During that period about 200 hectares bore flax for household needs. Since the scutching milis got going the area sown with flax for fibre production has been about 4000 hct. In 1950 4450 hectares were con-tracted to Swedish flax milis. In addition it is computed that there were 100—150 hect. bearing flax for household use. Climatic conditions during the years comprized in the collocation were varied and influenced the yield as regards both quality and quantity. Drought in spring and early summer hindered growth while heavy autumn rain lowered the quality and delayed the ingathering. Variety experiments The following varieties have been the object of experimentation: The Swedish Svalöf institution contributed Hercules, Blenda, Gerda, Margareta,